华北地区下古生界白云岩类型与储集性

TYPE AND RESERVOIR PROPERTY OF THE LOWER PROTEROZOIC DOLOSTONES IN THE NORTH CHINA

本区具有造岩规模的白云岩归属四种成因类型:同生白云岩、准同生白云岩、成岩白云岩和后生白云岩,主要分布层位是奥陶系,次为寒武系上统和下统。 生成于水下蒸发环境中的同生白云岩可作盖层;生成于水上蒸发成岩环境中的准同生白云岩和浅埋地下成岩环境的成岩白云岩,是较好的储集层;怀远期不整合面以下的透镜状次生白云岩储集性差。

Four genetic types of diagenesis are defined for the dolostones as:syngenetic,para-syngenetic di-agenetic and epigenetic dolostones, which are mainly attributed to the Ordovician systems partly to the upper and lower Cambrian systems. Syngenetic dolostones formed in an environment of under water evaporation can be cover rocks while those in a diagenetic environment of overwater evaporation, and diagenetic dolostonss in a snallow buried diagenetic environment are of fairly good reservoir rocks. But the secondary lenticular dolostones occurred beneath the unconfority of the Huaiyuan Period are poor reservoir rocks.